
DS2782: Stand-Alone Fuel Gauge IC 
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INITIATING COMMUNICATION IN SLEEP 
When beginning communication with a DS2782 in PMOD SLEEP, the bus must be pulled up before a START bit 
can be issued by the master. In UVEN SLEEP, the procedure depends on the bus state when UVEN SLEEP was 
entered. If the bus was low, it must be pulled up before a START bit can be issued by the master as required with 
PMOD SLEEP. If the bus was high when UVEN SLEEP was entered, then the DS2782 is prepared to receive a 
START bit from the master. A standard procedure of issuing a START – STOP – START when the host system is 
powered up on the charger input properly initiates communication from both PMOD and UVEN SLEEP modes. 
VOLTAGE MEASUREMENT 
Battery voltage is measured at the VIN input with respect to VSS over a range of 0V to 4.992V, with a resolution of 
4.88mV. The result is updated every 440ms and placed in the VOLTAGE register in two’s compliment form. 
Voltages above the maximum register value are reported at the maximum value; voltages below the minimum 
register value are reported at the minimum value. The format of the voltage register is shown in Figure 4. 
Figure 4. Voltage Register Format 
VOLT
Read Only
MSB—Address 0Ch 
LSB—Address 0Dh 
S 
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
X 
X 
X 
X 
X 
MSb  
LSb  
MSb  
LSb
“S”: sign bit(s), “X”: reserved 
Units: 4.88mV
VIN is usually connected to the positive terminal of a single cell Lithium-Ion battery via a 1k  resistor. The input 
impedance is sufficiently large (15M ) to be connected to a high impedance voltage divider in order to support 
multiple cell applications. The pack voltage should be divided by the number of series cells to present a single cell 
average voltage to the VIN input. In Figure 3, the value of R can be up to 1M  without incurring significant error 
due to input loading. 
TEMPERATURE MEASUREMENT 
The DS2782 uses an integrated temperature sensor to measure battery temperature with a resolution of 0.125°C. 
Temperature measurements are updated every 440ms and placed in the temperature register in two’s complement 
form. The format of the temperature register is shown in Figure 5.  
Figure 5. Temperature Register Format 
TEMP 
Read Only
MSB—Address 0Ah 
LSB—Address 0Bh 
S 
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
X 
X 
X 
X 
X 
MSb  
LSb  
MSb  
LSb
“S”: sign bit(s), “X”: reserved 
Units: 0.125 C